1. Field of the Invention
This invention relates to a support member for resiliently urging a film cassette of a first configuration into position for the exposure of a film unit contained therein and for preventing a film cassette of a second configuration from being so positioned.
2. Description of the Prior Art
Oftentimes there are occasions when one wants to prevent the full insertion of a film cassette into a film chamber. For example, as taught in U.S. Pat. No. 3,672,276, inadvertent insertion of a film cassette into a film chamber in an upside down manner is precluded by providing the film cassette and the walls of the film chamber with complimentary ribs and grooves. Also, see U.S. Pat. No. 3,682,076 wherein a film cassette supporting spring is constructed to preclude the full insertion of a film cassette into a film chamber in an upside down manner.
It is important that the full insertion of a film cassette into the film chamber of a camera be prevented when one or more of the exposure parameters of the film units located within the film cassette, e.g., film speed, does not correspond with one or more of the exposure parameters of the exposure system of the camera. This is especially true where the film cassette containing the wrong type of film units is very similar to the one which is normally inserted into the camera. Accordingly, it can be seen that there is a need to provide a camera with means for permitting the full insertion into a film chamber of a film cassette containing film units which are compatible with the camera, and for rejecting those cassettes which contain film units which are not compatible with the camera. Preferably, these means should perform a plurality of other functions, e.g., prevent insertion of the film cassette in an upside down manner and support a film cassette in position for the exposure of a film unit located within the film cassette.